Engines

ABSTRACT

An engine comprising a rotary piston support defining a piston bore, a porting surface and a conduit extending from the bore to the porting surface, a cam movable relative to the support and defining a generally annular cam surface of 2n cycles arranged in n sets each of two cycles, one cycle of each set being adjacent and having a displacement greater than that of the other cycle of the set, a piston mounted in the bore for movement relative to the support and engaging the cam surface, a manifold fixed with respect to the cam and defining at a porting surface thereof 4n ports arranged in n sets each of four conduits, each cycle having at least one manifold port associated therewith, a power chamber including means for increasing the internal energy of a gaseous fluid therein, and four conduits providing for, respectively, intake flow to the bore, flow from the bore to the chamber, and from the chamber to the bore, and for exhaust from the bore.

O United States Patent 1191 1111 3,854,284

Denker Dec. 17, 1974 [54] ENGINES 3,662,551 /1972 Denker 60/4683,687,1l7 8 1972 P 't' I23 43 A [75] Inventor: James M. Denker,Sc1tuate, Mass. 8mm 1 l [73] Assignee: Nutron Corporation, Hingham,Primary Examiner-Clarence R. Gordon Mass.

22 Filed: Apr. 25, 1973 ABSTRACT [21] Appl No; 354,209 An enginecomprising a rotary piston support defining a piston bore, a portingsurface and a conduit extend- Related Apphcatlon Data ing from the boreto the porting surface, a cam mov- [63] Continuation-in-part of Ser. No.185,727, Oct. 1, able relative to the support and defining a generally1971- annular cam surface of Zn cycles arranged in n sets each of twocycles, one cycle of each set being adja- Cl cent and having adisplacement greater than that of 60/5 /65, the other cycle of the set,a piston mounted in the 123/43 23/ C bore for movement relative to thesupport and engag- [5l] Int. Cl. F02g 3/00 ing the cam surface, amanifold fixed with respect to Field Of Search 0/ 39.6, the cam anddefining at a porting surface thereof 4n /468; 123/43 A; 91/65, 501ports arranged in n sets each of four conduits, each cycle having atleast one manifold port associated [56] References Cited therewith, apower chamber including means for in- UNITED STATES PATENTS creasing theinternal energy of a gaseous fluid therein, 2,070,606 2/1937 Lickfeldt60/396] and four Conduits pmviding respectively intake 2442J25 3/1948Gunning 915m flow to the bore, flow from the bore to the chamber,3.104537 9/1963 Gese 60/3953 and from the chamber to the bore, and forexhaust 3,267,675 8/1966 Gesell 60 3961 from the bore. 3,310,043 3/1967Gamageu... 60/39.6l UX 3,403,599 l0/l968 Guinot 91/65 24 Clam, 6 D'awmgFgures RELIEF PATENTELEECI 71974 sum '1 OF FIG.

PAIENIE an". I 71974 SHEET 2 OF 3 PATENIEL DEC 1 7 I974 HEAT COMPRESSORTURBINE SHEET 3 OF 3 CLUTCH} FUEL STARTER 2 MOTOR 7 HEATER FIG. 6

ENGINES This invention relates to enginesThis application is acontinuation-in-part' of my copending application Ser. No. 185,727,filed Oct. 1, 1971, entitled Fluid Devices.

It is a principal object of the present invention to provide a compactand efficient rotary, reciprocating piston device that is the steadyflow equivalent of a turbine. Other objects include providing such adevice, having either axially or radially movable pistons, in which thepistons are alternately subjected to high and low temperature andalternately act as compressors and as greater displacement expanders.

The invention features an engine comprising a rotary piston supportdefining a piston bore, a porting surface and a conduit extending fromthe bore to the porting surface, a cam movable relative to the supportand defining a generally annular cam surface of Zn cycles arranged in nsets each of two cycles, one cycle of each set being adjacent and havinga displacement greater than that of the other cycle of the set, a pistonmounted in the bore for movement relative to the support and engagingthe cam surface, a manifold fixed with respect to the cam and definingat a porting surface thereof 4n ports arranged in n sets each of fourconduits, each cycle having at least one manifold port associatedtherewith, a power chamber including means for increasing the internalenergy of a gaseous fluid therein, and four conduits providing for,respectively, intake flow to the bore, flow from the bore to thechamber, and from the chamber to the bore, and for exhaust from thebore. In preferred embodiments wherein the amplitude-of the one cycle ofeach set is in the range of 1.5 to 3.0 times that of the othercycle ofthe set, n is not less than 2, the cam cycles are alternately arranged,each haIf-cycle has a manifold port associated therewith, and each setof manifold ports is associated with a set of cam cycles andcommunicates with the conduits, there is featured a source of gaseousfluid connected to the inlet; a source of fuel connected to the powerchamber or the inlet, or alternately, a heater for heating fluid in thepower chamber, a plurality of axial bores in the piston support, a pairof pistons in each bore, a pair of identical, oppositely facing annularcam surfaces, one piston in each bore engaging each cam surface, and acompressor for compressing the fluid prior to it being drawn into theinlet.

Other objects, features, and advantages will become apparent from thefollowing detailed disclosure of a preferred embodiment of theinvention, taken together with the attached drawings, in which:

FIG. 1 is a schematic diagram of an engine system including a rotarymotor and constructed in accordance with the present invention;

FIG. 2 is a longitudinal cross-sectional view of the rotary motor ofFIG. 1, the section taken at 2-2 of FIG. 3;

FIG. 3 is a partial transverse cross-section of the rotary motor of FIG.1, taken at 33 of FIG. 2;

FIG. 4 is a developed, somewhat diagrammatic view, of a cam of therotary motor of FIG. 1; and,

FIGS. 5 and 6 are schematic diagrams of other engine systems constructedaccording to the present invention and including rotary motors similarto that of FIG. 1.

Referring now to the drawings, there is shown in FIG. 1 an engine systemincluding and driving a rotary motor to which four flow lines,designated 3, 4, 6 and 7, are connected as described hereinafter. Airfrom an air source 1 and fuel from fuel source 2 are fed into motor 10through line 3. A combustion chamber 5 is connected to the motor bylines 4 and 6; and line 7 provides an exhaust to the atmosphere. Apressure relief valve 9 is connected to line 3 at the junction 8 of thelines extending from sources 1, 2. A starter ll, including aconventional glow plug 13, is provided for igniting the air-fuel mixturein combustion chamber 5.

As shown in FIGS. 2 and 3, rotary motor 10 comprises an output shaft 12extending coaxially through a multi-part housing including, in coaxialalignment, a cylindrical main housing 14, a cylindrical support housingsection 16 and end plate 18. At one end of the housing, output shaft 12is journaled within a roller bearing 20 (whose inner face engages theshaft periphery and whose outer face engages the inner wall of housingsection 14); at the other end of the housing, shaft 12 is journaledwithin a ball bearing 22 (whose inner face engages the shaft peripheryand whose outer face engages the inner wall of housing section 16).Rubber lip seals 24, 26 are provided intermediate and prevent leakagebetween shaft 12 and, respectively, housing section 14 and end plate 18.

A cylindrical fluid distribution manifold 30 and rotor 34 are mountedwithin annular cavities within main housing 14 and surrounding shaft 12.One axial face of rotor 34 is in face-toface engagement with theadjacent face 31 of manifold 30. A wave washer 32 engages the otheraxial face 33 of manifold 30 and the portion of main housing 14 definingthe adjacent end wall of the cavity. Rotor 34 is fixed on shaft 12 forrotation therewith by spline 40.

The inner cylindrical surfaces of housing 14, manifold 30 and housingsection 16 are of slightly greater diameter than are the portions of theouter peripheral surface of shaft 12 they respectively surround, therebyproviding annular chamber 38 about the shaft. Communication between theportions of chamber 38 on opposite sides of rotor 34 is provided byinterstitial passages of spline 40.

The various interfaces between parts of the motor, that is, theinterfaces between end plate 18 and support section 16, the interfacebetween support section 16 and main housing 14, and the interfacesbetween main housing 14 and manifold 30, are sealed with a plurality ofO-rings designated 42, 44, and 46, respectively. Pins and bolts 52 and54 locate and prevent relative rotation of manifold 30 and housing 14,housing 14 and housing section 16, and end plate 18 and housing section16, respectively.

Main housing 14 includes six drilled conduits, designated 100, 102, 104,106, 108, and 110, respectively, extending through the wall of the mainhousing section. The outer portion of each conduit is tapped forreceiving a coupling. As shown schematically in FIG. 1, conduit isconnected to inlet line 3, conduit 104 to exhaust line 7; and lines 4and 6 are respectively connected to conduits 106 and 102. Relief lines(not shown) are connected to the outer ends of conduits and 108.

A total of four, radially inwardly facing annular channels, 101, 103,105, and 107 are provided in housing section 14 at the periphery ofmanifold 30. Each channel communicates, as shown, with the inner end ofa respective one of conduits 100, 102, 104, and 106. The inner. end ofconduit 108 communicates with the annulus in which wave washer 32 ismounted; that of conduit l with the annular chamber 70 in which rotor 34is mounted.

As shown most clearly in FIG. 3, a total of eight drilled conduits, 56through 63, arranged in a ring and spaced at regular 45 intervalstherearound, extend axially within manifold 30 from surface 31. Conduits56 and 60 (see FIG. 2) extend axially to points opposite and thenceradially to channel 101. Similarly conduits 57 and 61, 58 and 62, and 59and 63 extend axially to points opposite and, thence radially to,respectively, channels 107, 103, and 105.

Rotor 34 includes a total of nine cylindrical bores 80 and ninecylindrical conduits 82 (arranged in a ring within the rings of bores80) extending axially through the full thickness of the rotor. The boresand conduits of each ring are evenly spaced about the circumference ofthe ring with one conduit 82 and one bore 80 from each of the two ringsin radial alignment. The rings of conduits 82 of rotor 34 (whichterminate in respective ports at surface 35) and of conduits 56-63 ofmanifold 30 (which terminate in respective ports at surface 31) are ofequal diameter. A drilled conduit 84 extends from each conduit 82 to thebore 80 aligned therewith. Two steel balls 86, urged apart by a helicalspring 87 are fitted within each of bores 80 for movement within thebore.

As shown, annular chamber 70, which is defined by adjacent surfaces ofrotor 34, housing 14 and housing section 16, is of substantiallyU-shaped cross-section and surrounds the portion of rotor 34 includingbores 80 and balls 86. Annular wave cams 88, 89 each including arespective circular undulating ball-engaging surface 90, 91 are mountedon opposite axial sides of rotor 34, coaxially therewith, with theball-engaging surface 90, 91 of each cam facing rotor 34 and engagingone of the balls 86 in each bore 80. The ball-engaging surfaces, 90, 91of earns 88, 89 are identical; each is a multi-cycle trapezoidalacceleration cam surface comprising alternating parabolic andintermediate fairing sections. The period of each cycle is 90 (that iseach entire annular surface includes four complete cycles each havingone high point or peak or one low point or valley), and the high points(peaks) of all cycles of each cam lie in a common plane. As showndiagrammatically in FIG. 4, the amplitudes (peak-to-valley distance) ofadjacent cycles are not equal. Rather cam 88 (and cam 89 which isidentical) includes two cycles of amplitude A and two cycles ofamplitude a. The cycles are alternately arranged and the displacement ofa cycle of amplitude A is 1.5 to 3.0 (as shown, 2.0) times that ofamplitude a.

Each of earns 88 and 89 is positioned within motor 10 coaxially withshaft 12 and with the low point of an A amplitude cycle of therespective cam aligned midway between conduits 58' and S9. Pins 92 holdthe cam in position.

Motor 10 is the equivalent of two independent submotors of differentdisplacements mounted on the same shaft. One submotor, submotor a,comprises those of balls 86 which are in contact with cam cycles ofamplitude a and has a displacement of about 2.5 cu. in. per revolutionof rotor 34. The other submotor, submotor A," comprises the balls incontact with the A- amplitude cam cycles and has a displacement of about5 cu. in. per revolution. Submotor a is connected between motor intakeconduit 100 and combustion chamber inlet conduit 106 and acts as acompressor; submotor A, connected between combustion chamber outletconduit 102 and exhaust conduit 104, acts as an expander. As indicatedin FIG. 4, which is a developed view of cam 88 with the ports ofconduits 56-63 superposed thereupon to illustrate the segment of the camwith which each conduit is associated, each pair of balls 86 in anyparticular rotor bore forms a part of submotor a during theapproximately of rotor rotation that the bore communicates with conduits56, 57 of manifold 30, and during the approximately 90 period ofcommunication with conduits 60, 61. During the respective 90 rotationperiods of communication with conduits 58, 59, and with conduits 62, 63,the balls in the bore form a part of submotor A.

In operation, air from source 1 and a combustible fuel from source 2 areintroduced into motor 10 through line 3 and intake conduit 100. Any of alarge number of fuels may, of course, be used. The choice will depend onsuch features as cost, availability, pollution effect, and the like. Theair-fuel mixture is drawn into the bores 80 of submotor a during therotational periods that the bores are in communication with manifoldconduits 56, 60, and is compressed by submotor a and discharged incompressed condition into combustion chamber 5 through line 4 andcombustion chamber inlet conduit 106 during the rotational period thatthe bores communicate with manifold conduits 57, 61.

In chamber 5, the compressed mixture is combusted, and increases greatlyin temperature and pressure. Generally, combustion in chamber 5 iscontinuous, and glow plug 13 is used only to ignite the mixture duringengine starting. The hot, high pressure gas is then discharged fromchamber 5 through line 6 and into the bores 80 of submotor A that are incommunication with ports 58, 62. The gas expands against the balls 86 inthese bores, forcing the balls outwardly against cam surfaces 90, 91 andcausing rotation of rotor 34. When the bores move into communicationwith ports 59, 63 the expanded gas is exhausted from motor 10 throughconduit 104 and line 7.

As is thus evident, each of bores 80 and the two balls 86 thereindefines a working chamber, the volume of which expands and contracts asrotor 34 rotates and the balls move in and out in contact with camsurfaces 90, 91. In the preferred embodiment, the ports of manifoldconduits 56, 60 are arranged so that fluid will be drawn into each ofthe working chambers of submotor a during the entire period that itsvolume is expanding. That is, conduits 56, 60 communicate with the bores80 during the entire period that the balls 86 in the bore are movingoutwardly on a cycle of amplitude a. Similarly, the ports of manifoldconduits 59, 63 are arranged so that fluid will be exhausted from theworking chambers of submotor A. during the entire period that theirvolume is decreasing; that is, during the period that the balls in boresare moving inwardly on a cycle of amplitude A.

For efficient operation, it is desirable that the working chambers ofsubmotor a be closed during an initial period during which their volumeis contracting (and thus compressing the fluid therein), and that theybe open to combustion chamber 5 (to force the compressed fluid into thecombustion chamber) during the remaining period of volume contraction.Accordingly, the ports of manifold conduits 57, 61 are arranged so thatthey are closed by rotor end face 35 during the initial period thatballs 86 are moving inwardly in contact with a cycle of amplitude a, andcommunicate with rotor conduits 82 during the remaining period that theballs are in contact with the amplitude a cycle.

Similarly, it is desirable for the working chambers of submotor A to beopen to combustion chamber 5 (to permit flow of high temperature andpressure fluid into the working chambers) during an initial period thatthe volume of the chambers is expanding, and to be closed (to permitadiabatic expansion of the fluid) during the remaining period of volumeexpansion. The ports of manifold conduits 58, 62 accordingly arearranged so that they communicate with rotor bores 82 during the initialperiod that balls 86 are moving outwardly in contact with a cycle ofamplitude A and are closed during the remaining period of ball contactwith the A amplitude cycle.

The exact period during which these ports are open and closed depends onthe desired working cycle of the engine. Typically, the ports ofconduits 57, 61 will open to combustion chamber 5 when the fluid insubmotor a has been compressed to about half its original volume and toa pressure equal to that in combustion chamber 5. The ports of conduits58, 62 similarly will typically remain open to combustion chamber 5until the submotor A working chamber has reached about half its maximumvolume.

Reference is now made to FIG. 5 wherein is illustrated an engine systemincluding and driving a motor which is identical to motor 10. Thoseportions of the FIG. 5 system corresponding to portions of the system ofFIGS. 14 are identified by the same numbers as their counterparts, witha differentiating prime added thereto.

As shown, the FIG. 5 system includes centrifugal air compressor 1connected by line 3 to motor inlet conduit 100'; an exhaust line 7extending from motor exhaust conduit 104'; and a combustion chamber 5;connected to motor conduits 102' and 106 by lines 6 and 4',respectively. Fuel from source 2 is sprayed directly into combustionchamber 5, rather than being mixed with air as in the FIG. 1 system. Asin the previously described system, a starter 11 including a glow plug13' is provided for igniting the fuel in combustion chamber 5. Anoverdrive clutch 119 is mounted on motor shaft 12', which also isconnected to and drives compressor 1. For starting motor 10 a startingmotor 121 drives shaft 12 through gears 123. The general operation ofthe FIG. 5 engine system is in substantially the same as that of thesystem of FIGS. 1-4.

FIG. 6 illustrates a heat engine system including and driving a motor10". As before, portions of the FIG. 6 system corresponding to portionsof the FIGS. l-4 system are identified by the same numbers with adifferentiating double prime added thereto.

As shown, the FIG. 6 system includes a gaseous heat exchanger 1 havingits outlet connected by line 3" to motor inlet conduit 100 and its inletconnected by line 7" to motor exhaust conduit 104". A fluid heatingchamber 5" is connected to motor conduits 102" and 106" by lines 6" and4", respectively. A heater 120, 6

which may be powered by any fuel source, is provided closely adjacentchamber 5" for heating the gaseous fluid therein. As is evident, thesystem of FIG. 6 differs from the systems previously described in threemajor respects. First, there is no combustible fuel added to the gaseousfluid passed through motor 10"; second, since it is a closed loopsystem, helium may be used rather than air as the expansible fluid and,third, coupled turbine compressor 124 and expander 122 are provided inlines 3" and 7", respectively, to increase overall efiiciency.

In operation, the gaseous fluid from heat exchanger 1" is introducedinto the motor through line 3" and turbine compressor 124, drawn intothe bores of submotor a where it is further compressed, and forced intochamber 5". In chamber 5", heat from source is applied to the fluid,increasing its pressure and temperature. The high energy fluid is thendischarged through line 6" into the bores of submotor A, expands againstthe balls 86 in these bores, and is finally exhausted from the motor andback to heat exchanger 1" through line 7" and turbine expander 122.

Other embodiments within the scope of the following claims will occur tothose skilled in the art.

What is claimed is:

1. An engine having an inlet port and an exhaust port and comprising:

a rotary piston support defining a piston bore, a porting surface, and aconduit extending from said bore to a port at said porting surface;

a cam defining a generally annular cam surface of Zn cycles, said cyclesbeing arranged in n sets each of two cycles, one cycle of each set beingadjacent and having a displacement greater than that of the other cycleof said each set, and said cam and said piston support being relativelyrotatable,

a piston mounted in said bore for movement relative to said support andengaging said cam surface;

a manifold fixed with respect to said cam and having a porting surfaceengaging said support porting surface, said manifold porting surfacedefining a plurality of ports, each of saidcycles having at least one ofsaid manifold ports associated therewith, said manifold ports beingarranged such that during the respective predetermined portions of therelative rotation of said manifold and said support that said pistonengages each said cycle said port at said support porting surfacecommunicates with said one manifold port associated with said eachcycle, and said manifold and said support being relatively movable;

a power chamber including means for increasing the internal energy of agaseous fluid therein;

a first conduit communicating with said inlet port and a first one ofsaid manifold porting surface ports and providing for intake flow offluid from said inlet port through said first one port to said bore;

a second conduit communicating with said power chamber and a second oneof said manifold porting surface ports and providing for flow of fluidfrom said bore through said second one port to said power chamber;

a third conduit communicating with said power chamber and a third one ofsaid manifold ports and providing for flow of fluid from said powerchamber through said third one port to said bore; and,

a fourth conduit communicating with a fourth one of said manifold portsand said exhaust port and providing for exhaust of fluid from said borethrough said fourth one port to said exhaust port.

2. The engine of claim 1 wherein said manifold porting surface defines4n ports arranged in n sets each including four ports, and each of saidmanifold ports is associated with a respective predetermined half-one ofsaid cycles and is arranged to communicate with said port of saidsupport during the period of relative rotation of said support and saidcam that said piston engages said respective predetermined half-one.

3. The engine of claim 2wherein each manifold port of each set of saidmanifold ports communicates with a respective one of said first, second,third, and fourth conduits.

4. The engine of claim 3 wherein each set of said manifold ports isassociated with a respective set of said cycles and communicates withsaid port of said support when said piston engages said respective set.

5. The engine of claim 1 wherein the displacement of said one cycle isin the range of 1.5 to 3.0 times the displacement of said other cycle.

6. The engine of claim 1 including a source of compressible fluidconnected to said inlet port and means for increasing the internalenergy of fluid in said chamber, whereby, in response to relativerotation of said cam and support, fluid from said source is drawn intoand compressed in said bore, discharged in compressed condition intosaid chamber, and thereafter increased in internal energy and dischargedfrom said chamber.

7. The engine of claim 6 wherein said fluid is a combustion supportingfluid and including a source of combustible fuel and means forintermixing fuel from said source with said fluid and for combustingsaid mixed fuel and fluid in said chamber prior to discharge of the samefrom said chamber.

8. The engine of claim 7 wherein said means includes an ignitor.

9. The engine of claim 7 wherein said fuel source is connected to saidinlet port whereby said mixed fuel and fluid are drawn into said inletport.

10. The engine of claim 7 wherein said fuel source is connected to saidchamber and including means for injecting said fuel into said chamber.

11. The engine of claim 6 wherein said means for increasing saidinternal energy includes a heater for noncombustingly heating fluidwithin said chamber.

12. The engine of claim 6 including a compressor intermediate said fluidsource and said inlet port for compressing fluid from said source priorto said fluid being drawn into said inlet port.

13. The engine of claim 12 including an expander connected to saidexhaust port and arranged to be driven by fluid from said exhaust port,said expander being coupled to and driving said compressor.

14. The engine of claim 1 wherein said support includes a plurality ofpiston bores and a conduit extending from each of said bores to arespective port at said support porting surface, each of said respectiveports being arranged successively to communicate with said manifoldports during relative rotation of said support and said manifold, and apiston is mounted in each of said bores for movement therein inengagement with said cam surface.

15. The engine of claim 14 wherein n is not less than 2 and thedisplacement of each cycle of one set is equal to the displacement of arespective cycle of each of the others of said sets. I

16. The engine of claim 15 wherein the displacement of said one cycle isin the range of 1.5 to 3.0 times the displacement of said other cycle.

17. The engine of claim 14 wherein said manifold porting surface defines4n ports arranged in n sets each of four ports, each set of said cyclesis associated with a respective one of said sets of manifold ports, andeach of said pistons engages said each set of said cycles during theportion of relative rotation of said support and said cam that said portof said conduit associated with said each piston communicates with themanifold ports of said respective one of said sets of manifold ports.

- 18. The engine of claim 17 including a second cam identical to saidfirst-mentioned cam, and a second piston mounted in each of said boresfor movement therein in engagement with said second cam, each of saidcams being fixed with respect to said manifold with corresponding cyclesthereof in axial alignment with each other.

19. The engine of claim 17 wherein each of said piston bores and thepiston therein provides a working chamber the volume of which changesduring rotation of said rotor relative to said cam with said piston incontact with said cam, and

each port of said manifold communicating with said second conduit andthe respective rotor port associated with said each bore are arrangedsuch that flow therebetween is prevented during an initial portion ofthe period of said rotation that the volume of said working chamber iscontracting with said piston in contact with a said other cycle and thatflow therebetween is permitted during a remaining portion of saidperiod.

20. The engine of claim 17 wherein each of said piston bores and thepiston therein provides a working chamber the volume of which changesduring rotation of said rotor relative to said cam with said piston incontact with said cam, and

each port of said manifold communicating with said third conduit and therespective rotor port associated with said each bore are arranged suchthat flow therebetween is permitted during an initial portion of theperiod of said rotation that the volume of said working chamber isexpanding with said piston in contact with a said one cycle and thatflow therebetween is prevented during a remaining portion of saidperiod.

21. The engine of claim 20 wherein said initial period commences whensaid volume begins to expand and ends when said volume reaches aboutone-half its maximum volume. I

22. The engine of claim 21 wherein each port of said manifoldcommunicating-with said second conduit and the respective rotor portassociated with said each bore are arranged such that flow therebetweenis prevented during the portion of said rotation with said piston incontact with a said other cycle commencing where said volume begins tocontract and ending when said volume is about one-half the volume atsuch beginning, and that such flow is permitted during the remainingportion of said rotation with said piston in contact with said othercycle.

manifold communicating with said fourth conduit and the respective rotorport associated with said each bore are arranged such that flowtherebetween is permitted substantially throughout the portion of saidrotation with said piston in contact with a said one cycle that saidvolume is contracting.

1. An engine having an inlet port and an exhaust port and comprising: arotary piston support defining a piston bore, a porting surface, and aconduit extending from said bore to a port at said porting surface; acam defining a generally annular cam surface of 2n cycles, said cyclesbeing arranged in n sets each of two cycles, one cycle of each set beingadjacent and having a displacement greater than that of the other cycleof said each set, and said cam and said piston support being relativelyrotatable, a piston mounted in said bore for movement relative to saidsupport and engaging said cam surface; a manifold fixed with respect tosaid cam and having a porting surface engaging said support portingsurface, said manifold porting surface defining a plurality of ports,each of said cycles having at least one of said manifold portsassociated therewith, said manifold ports being arranged such thatduring the respective predetermined portions of the relative rotation ofsaid manifold and said support that said piston engages each said cyclesaid port at said support porting surface communicates with said onemanifold port associated with said each cycle, and said manifold andsaid support being relatively movable; a power chamber including meansfor increasing the internal energy of a gaseous fluid therein; a firstconduit communicating with said inlet port and a first one of saidmanifold porting surface ports and providing for intake flow of fluidfrom said inlet port through said first one port to said bore; a secondconduit communicating with said power chamber and a second one of saidmanifold porting surface ports and providing for flow of fluid from saidbore through said second one port to said power chamber; a third conduitcommunicating with said power chamber and a third one of said manifoldports and providing for flow of fluid from said power chamber throughsaid third one port to said bore; and, a fourth conduit communicatingwith a fourth one of said manifold ports and said exhaust port andproviding for exhaust of fluid from said bore through said fourth oneport to said exhaust port.
 2. The engine of claim 1 wherein saidmanifold porting surface defines 4n ports arranged in n sets eachincluding four ports, and each of said manifold ports is associated witha respective predetermined half-one of said cycles and is arranged tocommunicate with said port of said support during the period of relativerotation of said support and said cam that said piston engages saidrespective predetermined half-one.
 3. The engine of claim 2 wherein eachmanifold port of each set of said manifold ports communicates with arespective one of said first, second, third, and fourth conduits.
 4. Theengine of claim 3 wherein each set of said manifold ports is associatedwith a respective set of said cycles and communicates with said port ofsaid support when said piston engages said respective set.
 5. The engineof claim 1 wherein the displacement of said one cycle is in the range of1.5 to 3.0 times the displacement of said other cycle.
 6. The engine ofclaim 1 including a source of compressible fluid connected to said inletport and means for increasing the internal energy of fluid in saidchamber, whereby, in response to relative rotation of said cam andsupport, fluid from said source is drawn into and compressed in saidbore, discharged in compressed condition into said chamber, andthereafter increased in internal energy and discharged from saidchamber.
 7. The engine of claim 6 wherein said fluid is a combustionsupporting fluid and including a source of combustible fuel and meansfor intermixing fuel from said source with said fluid and for combustingsaid mixed fuel and fluid in said chamber prior to discharge of the samefrom said chamber.
 8. The engine of claim 7 wherein said means includesan ignitor.
 9. The engine of claim 7 wherein said fuel source isconnected to said inlet port whereby said mixed fuel and fluid are drawninto said inlet port.
 10. The engine of claim 7 wherein said fuel sourceis connected to said chamber and including means for injecting said fuelinto said chamber.
 11. The engine of claim 6 wherein said means forincreasing said internal energy includes a heater for non-combustinglyheating fluid within said chamber.
 12. The engine of claim 6 including acompressor intermediate said fluid source and said inlet port forcompressing fluid from said source prior to said fluid being drawn intosaid inlet port.
 13. The engine of claim 12 including an expanderconnected to said exhaust port and arranged to be driven by fluid fromsaid exhaust port, said expander being coupled to and driving saidcompressor.
 14. The engine of claim 1 wherein said support includes aplurality of piston bores and a conduit extending from each of saidbores to a respective port at said support porting surface, each of saidrespective ports being arranged successively to communicate with saidmanifold ports during relative rotation of said support and saidmanifold, and a piston is mounted in each of said bores for movementtherein in engagement with said cam surface.
 15. The engine of claim 14wherein n is not less than 2 and the displacement of each cycle of oneset is equal to the displacement of a respective cycle of each of theothers of said sets.
 16. The engine of claim 15 wherein the displacementof said one cycle is in the range of 1.5 to 3.0 times the displacementof said other cycle.
 17. The engine of claim 14 wherein said manifoldporting surface defines 4n ports arranged in n sets each of four ports,each set of said cycles is associated with a respective one of said setsof manifold ports, and each of said pistons engages said each set ofsaid cycles during the portion of relative rotation of said support andsaid cam that said port of said conduit associated with said each pistoncommunicates with the manifold ports of said respective one of said setsof manifold ports.
 18. The engine of claim 17 including a second camidentical to said first-mentioned cam, and a second piston mounted ineach of said bores for movement therein in engagement with said secondcam, each of said cams being fixed with respect to said manifold withcorresponding cycles thereof in axial alignment with each other.
 19. Theengine of claim 17 wherein each of said piston bores and the pistontherein provides a working chamber the volume of which changes duringrotation of said rotor relative to said cam with said piston in contactwith said cam, and each port of said manifold communicating with saidsecond conduit and the respective rotor port associated with said eachbore are arranged such that flow therebetween is prevented during aninitial portion of the period of said rotation that the volume of saidworking chamber is contracting with said piston in contact with a saidother cycle and that flow therebetween is permitted during a remainingportion of said period.
 20. The engine of claim 17 wherein each of saidpiston bores and the piston therein provides a working chamber thevolume of which changes during rotation of said rotor relative to saidcam with said piston in contact with said cam, and each port of saidmanifold communicating with said third conduit and the respective rotorport associated with said each bore are arranged such that flowtherebetween is permitted during an initial portion of the period ofsaid rotation that the volume of said wOrking chamber is expanding withsaid piston in contact with a said one cycle and that flow therebetweenis prevented during a remaining portion of said period.
 21. The engineof claim 20 wherein said initial period commences when said volumebegins to expand and ends when said volume reaches about one-half itsmaximum volume.
 22. The engine of claim 21 wherein each port of saidmanifold communicating with said second conduit and the respective rotorport associated with said each bore are arranged such that flowtherebetween is prevented during the portion of said rotation with saidpiston in contact with a said other cycle commencing where said volumebegins to contract and ending when said volume is about one-half thevolume at such beginning, and that such flow is permitted during theremaining portion of said rotation with said piston in contact with saidother cycle.
 23. The engine of claim 22 wherein each port of saidmanifold communicating with said first conduit and the respective rotorport associated with said each bore are arranged such that flowtherebetween is permitted substantially throughout the portion of saidrotation with said piston in contact with a said other cycle that saidvolume is expanding.
 24. The engine of claim 23 wherein each port ofsaid manifold communicating with said fourth conduit and the respectiverotor port associated with said each bore are arranged such that flowtherebetween is permitted substantially throughout the portion of saidrotation with said piston in contact with a said one cycle that saidvolume is contracting.